Children with autism and autistic spectrum disorder (ASD) suffer from defects in socialization, verbal and nonverbal communication, and response to sensory stimuli. While the cause of autism is unknown, children with autism and ASD have been noted in several studies to have a high prevalence of macrocephaly and appear to be taller on average than the general population. Growth patterns and markers of maturation in autistic children have not been studied in detail. Dehydroepiandrosterone sulfate (DHEA-S), a marker for adrenal maturation, is low in early childhood but increases during the mid-growth spurt (about age 6-8). DHEA-S concentration appeared to be elevated in autistic children compared with normal controls in one previous study, raising questions about the possibility that early elevations of DHEA-S in autistic children may be associated with large head and body size. Other methods of assessing maturation in autistic children, such as bone age, have not been explored. We will use cross-sectional data to assess growth and maturation of children with autism/ASD in 3 ways: 1) the height, weight, body mass index (BMI) and head circumference children with autism/ASD between 4 and 8 years of age will be compared with developmentally normal age-, gender-, and race-matched controls, 2) DHEA-S levels children with autism/ASD will be compared with the same developmentally normal controls, and 3) bone age in children with autism/ASD will be compared with reference populations. Case children are currently being recruited from a clinic where a large number of autistic children are seen. Control children are being recruited at an outpatient surgery facility where tonsillectomy/adenoidectomy procedures are performed. Nearly all (96%) of the target number of cases and 70% of the control subjects have been recruited.